Chapter 12 · Core Rules
Magic
Philosophy
Magic dominates combat in Cerberus. At equal power, it is not balanced against martial characters. An accomplished caster ranks among the world's most dangerous forces. This power is earned slowly through study and play (see 5). Every spell defines its damage, duration, and range.
Paths of Power
Each race draws magic from a different source. This table summarizes their mechanical differences; the world book develops their origins and place in Cerberus societies.
| Path | Users | Mechanical Trait |
|---|---|---|
| Red Magic | Humans | Most powerful and abundant, but chaotic: low-level spells have short durations, and enchantments cost fortunes in gold. Poor at healing, hence alchemy. |
| Divine Magic | Humans of the Ark | Stabilized red magic: fewer spells, but easier to execute without genius and cheaper to enchant. |
| Psychic Magic | Drows, Psychics, psychic monsters, Monks of Kaz'Nakaram | Stable, normally requiring neither speech nor gesture. Recovery follows the source: converted human mana recovers like red mana, while innate and implanted reserves depend on meditation (see 4). |
| Runes | Dwarves | Dwarves ordinarily cast no spells; they slowly produce magical objects instead. |
Spell Memory
Magic leaves traces. When a person enters a room, they shed a few particles of red mana. These particles absorb fragments of the place around them: images, sounds, and emotions. Spell effects leave denser traces of the same kind.
This spell memory is not a creature's memory. It is the memory held by magical particles, and divination can explore it when a spell provides a way to gather or read those particles. A rich trace can preserve an illusion in great detail; a weak one may offer only a face, a cry, or the fear that filled the room.
Blue mana leaves a narrower and cleaner memory. It preserves the shape, direction, and intention of the Psychic act itself, but little unrelated scenery from the place around it.
DC and Saving Throws
When a spell acts on a creature, it resists with the appropriate Save (see 1):
- a spell striking the mind—fear, illusion, control—uses Will;
- a spell striking the body—poison, transformation, exhaustion—uses Fortitude.
An undead makes neither Save in the ordinary way; see 3.
The DC is:
DC = 10 + CL/2 + INT, plus any bonuses.
Roll the Save like every other Save: 1d20 + attribute + level, using the character's full level rather than half. Against an illusion, the Save occurs automatically once the character can perceive it; the GM rolls once at the beginning of the day and reuses that value.
The Caster's Three Resources
A mage manages three separate axes.
1. Spell slots, the reserve. A character carries an ocean of mana in the blood. Concentration capacity, or mental maturity, limits how many spells can be cast. Slots represent that limit:
Slots = 4 per spell level + ½ CHA.
A mage with +6 Charisma therefore has 7 slots per spell level (4 + 3). Casting a Level N spell spends a Level N slot; metamagic spends more. A higher-level slot can also pay for a lower-level spell, but the difference is lost. This is legal and rarely desirable. Whenever a spell, feat, or other rule requires additional spell slots, each of those slots must also be of the spell's level or higher. A lower-level slot can never pay any part of that cost.
Psychics and monsters call this unit a spell slot. The Monks of Kaz'Nakaram call it a Ki point. The names are mechanically identical: one Ki point equals one spell slot.
Recovering Slots
Mana is not the scarce resource. The ocean in the blood continually renews itself; the mage's concentration is what tires and rests. Slots are therefore the only reserve the game tracks. The rates below apply to red and divine magic, as well as blue powers converted from a human's red mana. Innate blue reserves follow their own meditation rules (see 4).
| Rest | Per Hour | Result |
|---|---|---|
| True Rest (sleep, meditation) | 20% of slots at each level | full reserve in 5 hours |
| Active Rest (walking, watch, study) | 10% of slots at each level | 50% ceiling in 5 hours |
Each spell level recovers separately at the same rate. A mage cannot sacrifice minor spells to recover powerful ones faster.
Calculate from the beginning of rest, not hour by hour. Multiply the rate by elapsed hours, then round down once under 1. For a reserve of 7 slots per level:
| Hours of True Rest | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Slots Recovered per Level | 1 | 2 | 4 | 5 | 7 |
Rounding every hour instead of the total would make recovery slower as the reserve grows.
The rate is identical at every level. A CL 5 mage recovers 4 slots per hour from a reserve of 21; a CL 20 mage recovers 16 from a reserve of 81. Absolute values explode, but recovery time does not change: five hours to refill and five hours to reach the ceiling. Blue spell slots do not follow this rule; see 4.
2. Spells per round, the action economy. This determines how many spells can be cast during one round, independently of the reserve: 2 at Level 1, 3 at Level 5, and 4 at Level 9 (see 5).
3. caster level, raw power. This determines each spell's strength.
At equal level, a charismatic mage has more slots and uses more metamagic; an intelligent mage has better DCs and crafting, adjudicated by the GM; a quick mage with Dexterity and feats wins Reflex duels and releases spells before opponents.
caster level
caster level (CL) is the caster's magical density—power in its pure form.
Every character begins at CL 1. A human adds 1 CL per 2 points of Charisma, rounded down: red mana answers to Charisma, and that is racial rather than studied (see 5). Everything else is earned during play and awarded by the GM; a specialized class can improve the ratio (Using Classes). CL then governs two things.
Magnitude. Damage, durations—often “X rounds per CL”—animal-form HP such as “10 HP per CL,” and range scale with CL. Each spell provides its formula. Casters follow the power curve through CL as martial characters follow it through Strength and weapons (see 5).
Access to High Levels. A slot is not enough. To cast a Level N version of a spell, a character must satisfy two independent conditions:
- they learned that version and reached its mastery level in the story;
- their caster level reaches the minimum in the table.
Three thresholds structure the required power—Level 1: CL 1; Level 9: CL 20; Level 10: CL 30—with the intervening values below:
| Spell Level | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|---|---|---|---|---|---|---|---|---|---|---|
| Minimum CL | 1 | 3 | 5 | 7 | 9 | 11 | 14 | 17 | 20 | 30 |
caster level measures available power, not maturity. A CL 10 Wizard who has learned only Level 2 spells remains limited to Level 2 even though that CL could technically fuel a Level 5 spell. High CL strengthens known spells without teaching more complex formulas.
Conversely, knowing a formula does not provide the minimum power. A Wizard who studied a Level 5 spell but has CL below 9 must wait until that power reaches the threshold.
When creating a Level N Wizard or Cleric directly, the story can normally be assumed to provide mastery through Level N, but not the next level. A Level 5 character may therefore know Level 5 spells, never Level 6 merely by assumption. They must still meet minimum CL, know the relevant spells, and possess the slots. The GM can assign lower mastery when the story describes a powerful but inexperienced or uneducated character.
The GM can therefore increase CL without raising mastery or character level. Known spells become stronger, but no new spell level unlocks automatically.
At very high CL, abjuration becomes devastating. A mage whose CL greatly exceeds an opposing effect can dispel or counter it without understanding its construction, temporarily deactivate a permanent enchantment, or even destroy it. See 15 for the added difficulty of magical objects.
Casting a Spell: Casting Time and Interruption
Most spells take two ticks, or two-thirds of a round. A spell designed to take longer, three ticks or more, can be more powerful at the same level; metamagic can instead accelerate it.
The caster remains vulnerable during casting. Cerberus uses no “concentration check.”
If the caster takes more than 25% of maximum HP while casting, the spell fails: the slot and action are lost. Below that threshold, the caster takes damage but completes the spell.
Stable blue mana raises this threshold by 10 percentage points. A blue spell fails only when its caster takes more than 35% of maximum HP during the casting.
The Reflex duel from 1 determines who acts first. A quick archer or rogue can interrupt the mage before the incantation ends.
Mage: I cast Fireball at the archer. DC... no, there is no DC; it deals direct damage. Archer: I loose an arrow before he finishes. GM: Reflex duel, both of you. Archer: 24. Mage: 19. Ouch. GM: The arrow leaves first. (It deals 18% of the mage's maximum HP—below the threshold.) It sinks into his shoulder. He grimaces but holds steady and completes the gesture. The archer disappears into the fireball.
Had the arrow exceeded 25%, the spell would have died on his lips, losing slot and round.
Maintaining a Spell through Concentration
A concentration spell remains active while its caster devotes attention to it. After casting, the caster spends one spell token per round to maintain the spell. That token occupies one Action Board slot during a tick chosen by the caster; the other two ticks remain available. Maintenance spends no new spell slot.
If no tick is devoted to the spell before the round ends, concentration breaks and the spell ends. During the maintenance tick, damage can interrupt concentration like an incantation: taking more than 25% of maximum HP ends the maintenance and the spell. Use the blue threshold of 35% when the maintained spell is powered by blue mana.
Each maintained spell requires its own spell token. A character maintaining two spells must devote two ticks per round unless a feat or power says otherwise. A spell can impose another rhythm or become autonomous at a higher level; its text then takes precedence.
Concentration does not automatically grant the target another Save. The spell states when resistance can be attempted again. With Hold, for example, the victim makes a Will Save every tick while the caster devotes only one of the round's three ticks to maintenance.
Resolving Offensive Spells
A direct damage spell allows no Save: it deals damage. Defense has three forms: interrupt the incantation, reach cover, or intercept it with a sufficiently powerful shield or weapon, blocking half (see 11). Armor DR then subtracts from what reaches the target, as against a weapon blow. Area spells are especially powerful.
At the GM's discretion, a sufficiently quick creature can make a Reflex Save to leave the radius of an area spell. Reserve this option for high-level characters with exceptional Reflex.
Metamagic
Metamagic feats bend a spell to the caster's will, and most are paid for in additional spell slots. The spell's own slot is always spent as well.
| Feat | Additional slots | What it changes |
|---|---|---|
| Long Spell | +4 | The duration rises one category |
| Quicken Spell | +3 | A casting time of 2 or 3 ticks falls to 1 |
| Delay Spell | +1 | The effect lies dormant, then fires on its own |
| Form Cascade | +1 | A broken Polymorph form gives way to another |
| Overcast | Higher-level slot | +50% base damage per level of difference |
| Additional Target | — | A single-target spell reaches several |
| Suspend Spell | — | A finished spell is held, then released later |
| Efficient Spell | −1 | Close range falls to Touch |
Efficient Spell is the only discount. It applies once per casting, however many feats modify that casting, and never reduces the cost below the spell's own slot.
Removing a component—verbal, somatic, or material—has no feat of its own. When a caster finds a way to do it, the GM prices it as metamagic: the spell becomes more complex, and therefore more expensive in slots.
Metamagic exhausts the reserve quickly even for a charismatic mage.
Meta-Spells
A meta-spell is a learned spell whose formula transforms, contains, or gives a new shape to another known spell. That other spell is called the source spell. For example, Elemental Wall turns elemental magic into a lasting wall, while Spell Trap holds a spell until its trigger occurs.
A meta-spell is not metamagic. It must be learned like any other spell and has its own entry. That entry states which source spells qualify, which levels they may have, and which spell slots are spent or committed. Unless the entry says otherwise, a meta-spell borrows only the parts of the source spell that it explicitly names.
Cooperative Casting
Several casters can cast one spell together. This is cooperative casting, or a ritual when extended over hours. One sorcerer casts the spell—the primary sorcerer—while the others lend power.
Cooperation raises the spell's caster level and nothing else. The spell remains entirely the primary sorcerer's: spell list, slot, and components. DC uses only the primary sorcerer's Intelligence, even when a helper is more intelligent. Helpers contribute no spells, feats, or attributes—only caster level.
Who Can Cooperate. Sorcerers must have comparable power: a master cannot be pushed by a crowd of apprentices. Compare each helper with the primary sorcerer.
Allowed caster level gap: 5 CL, or 20% of the primary sorcerer's CL when that is more generous, rounding the percentage down.
A CL 20 sorcerer can accept help from CL 15; CL 50 from CL 40; CL 100 from CL 80; and two CL 3 and 4 apprentices can cooperate. The 5 CL allowance dominates through CL 25; beyond that, 20% takes over and the circle widens as mages grow stronger.
The Price Is Time. Each additional sorcerer adds 3 ticks to casting time. The spell still costs only one slot, paid by the primary sorcerer; helpers spend time and expose themselves. Each remains vulnerable throughout casting under the 25% rule above.
A helper's contribution depends on their own caster level. Each value holds until the next threshold:
| Helper's CL | Contribution |
|---|---|
| 1 to 4 | +1 CL |
| 5 to 19 | +2 CL |
| 20 to 24 | +3 CL |
| 25 to 29 | +4 CL |
| 30 or higher | +5 CL, then +1 CL per interval of 5 |
Ceiling: cooperation never adds more than 50% of the primary sorcerer's caster level. A CL 20 sorcerer never exceeds CL 30 regardless of the number of colleagues. Beyond the ceiling, the competing wills interfere rather than combine.
It increases magnitude, not access. The primary sorcerer must already be able to cast the spell alone. Judge minimum CL for spell level from the primary's own CL before contributions. A gathering of CL 25 casters does not unlock Level 10 spells.
If Casting Breaks. A helper who takes more than 25% of maximum HP loses their contribution, and the spell continues at reduced CL. If the primary sorcerer takes that damage, the spell fails entirely and the slot is lost. Protecting the circle is part of the plan.
Example. Three House Alois mages want to subjugate a prisoner with Dominate. Gérard leads: CL 20, INT +9. The allowed gap is 5 CL, placing his colleagues at CL 15 and CL 20 inside the window, with the first exactly at its edge.
CL 15 contributes +2, and CL 20 contributes +3, so the spell resolves at CL 25. The ceiling is CL 30 and is not reached. DC rises from 10 + 20/2 + 9 = 29 to 10 + 25/2 + 9 = 31.5, therefore DC 31—using Gérard's Intelligence even though his CL 20 colleague is sharper. Dominate is Standard, so casting takes 2 + 3 + 3 = 8 ticks, nearly three full rounds.
This is why cooperation belongs in rituals, sieges, and interrogations rather than duels, except with the Cooperative Caster feat.
Alchemy
Alchemy is the human Cerberus path around red magic's poor healing. An alchemist combines their blood with ingredients to make a potion that must be drunk almost immediately or lose its effect. Ingredients let alchemy produce effects no spell can create.
Casting through Alchemy
An Arcane or Divine sorcerer normally shapes a spell through verbal and somatic components, sometimes adding a material component. An alchemist reaches the same magic primarily through material components: ingredients are mixed into an unstable solution during the spell's casting time. A particular formula can still require verbal or somatic components; its spell entry remains authoritative.
The listed casting time is the entire process for either method. A Standard spell takes 2 ticks for a sorcerer to shape and release. Its Alchemy version takes the same 2 ticks to prepare and immediately drink, apply, or throw. Delivery occurs as part of the final casting tick and requires no additional general action. If the unstable solution is not delivered immediately, its magic collapses and the spell is lost.
Quicken Spell works on both methods. By spending its additional slots, the sorcerer completes the incantation in 1 tick, while the alchemist prepares and delivers the unstable solution in 1 tick. Either casting can still be interrupted during that tick.
An unstable alchemical casting is not a stored potion. A potion stabilized through a long crafting ritual exists before combat and is later consumed with the normal 1-tick general action. Quicken Spell accelerates the live preparation of an Alchemy spell; it does not shorten the action required to retrieve, drink, or apply a potion crafted in advance.
To make a potion—or any spell—permanent, wrap it in gold. Gold forms a barrier that prevents magical particles from escaping and stabilizes the effect. Object enchantment relies on the same barrier (see 15).
Crafting a Preparation
Alchemical crafting is entirely GM-driven. A known recipe, clean ingredients, enough time, and a suitable laboratory can make success obvious: no roll. When interesting uncertainty remains, the GM announces a prescribed chance check and considers:
- the alchemist's experience and Intelligence;
- whether the recipe is known;
- freshness, rarity, and quantity of ingredients;
- time genuinely devoted to the work;
- distractions, transport, and local conditions;
- equipment quality.
An Alchemist's Kit, a Master Alchemist's Kit, and a Portable Alchemical Laboratory therefore grant no universal numerical bonus. They change the circumstances assessed by the GM: a preparation impossible with a knife and bowl may become risky with a kit, reasonable with master instruments, and routine in a laboratory. Equipment never replaces the main ingredient or knowledge of the recipe.
Before the roll, the GM also announces the risk: lost ingredient, fewer doses, unstable preparation, accidental exposure, or wasted time. Failure does not create an unrelated extra consequence.
Learning Magic
Spells are not learned by gaining a level. Learning happens during play through the character's choices. A player devotes one month of game time to studying a new spell; after that month, the GM grants it. This keeps progression slow and tied to the character's decisions.
Learning a higher-level version of a known spell also requires study during play. It generally takes less time than learning an unfamiliar spell because the caster already understands the spell's foundation. The GM sets the time according to the difference in complexity, available instruction, and circumstances.
There is no maximum number of known spells. This applies especially to the Wizard and Cleric of Archon: their repertoire is limited by the time, means, and opportunities they actually had to learn, not by a class value.
A divine spell with an existing formula is generally learned faster than an arcane one. Its liturgy is stable, recorded, and designed for reproduction. Converting an arcane spell into a divine spell is considerable work: the formula must be redesigned for the mana of the Partage, stabilized, and transmitted. This research can take months or years.
Chapter Summary
- DC = 10 + CL/2 + INT. Defender's Save: 1d20 + attribute + level (mind → Will, body → Fortitude).
- Three axes: slots (4/spell level + ½ CHA, the reserve), spells per round (action economy), and caster level (power).
- Slots are the reserve. Red, divine, and converted human blue slots recover 20% of each level per hour of true rest, or 10% during active rest to a 50% ceiling. Innate blue reserves follow their own meditation rules.
- CL scales magnitude and sets the power threshold for high levels (CL 1 → spell 1, CL 20 → spell 9, CL 30 → spell 10), but never teaches them. Each spell level must also be earned in the story.
- Casting takes 2 ticks. Taking > 25% of maximum HP during that time causes a red spell to fail; stable blue mana raises the threshold to > 35%. A Reflex duel resolves priority.
- Damage spells allow no Save, only damage; the GM may grant Reflex to escape an area. Metamagic costs slots. Learning a spell takes about one month of study during play.